1. Chapter 7
Drugs
Kendall/Hunt

2. Objectives You will understand:
Chapter 7
Objectives
You will understand:
How to apply deductive reasoning to a series of analytical data.
The limitations of presumptive (screening) tests.
The relationship between the electromagnetic spectrum and spectroscopic analysis.
The dangers of using prescription drugs, controlled substances, over-the-counter medications, and illegal drugs.
Kendall/Hunt

3. Objectives, continued You will be able to:
Chapter 7
Objectives, continued
You will be able to:
Chemically identify illicit drug types.
Classify the types of illicit drugs and their negative effects.
Discuss the federal penalties for possession and use of controlled substances.
Explain the need for confirmatory tests.
Kendall/Hunt

4. Objectives, continued You will be able to:
Chapter 7
Objectives, continued
You will be able to:
Describe IR, UV-VIS spectroscopy, and GC-MS.
Present and interpret data with graphs.
Use the Physicians’ Desk Reference (PDR) to identify pills.
Use technology and mathematics to improve investigations and communications.
Kendall/Hunt

5. Chapter 7
Drugs and Crime
A drug is a natural or synthetic substance designed to affect the subject psychologically or physiologically.
“Controlled substances” are drugs that are restricted by law.
The Controlled Substances Act is a law that was enacted in 1970; it lists illegal drugs, their categories, and penalties for possession, sale, or use.
Kendall/Hunt

6. Controlled Substances Act
Chapter 7
Controlled Substances Act
Schedule I—high potential for abuse; no currently accepted medical use in the U.S.; a lack of accepted safety for use under medical supervision
Examples: heroin (diacetylmorphine), LSD, marijuana, ecstasy (MDMA)
Schedule II—high potential for abuse; a currently
accepted medical use with severe restrictions; abuse
may lead to severe psychological or physical
dependence
Examples: cocaine, morphine, amphetamines (including
methamphetamines), PCP, Ritalin
Kendall/Hunt

7. Controlled Substances Act, continued
Chapter 7
Controlled Substances Act, continued
Schedule III—lower potential for abuse than the drugs in I or II; a currently accepted medical use in the U.S.; abuse may lead to moderate physical dependence or high psychological dependence
Examples: intermediate-acting barbiturates, anabolic steroids, ketamine
Schedule IV—low potential for abuse relative to drugs in III; a
currently accepted medical use in the U.S.; abuse may lead to
limited physical or psychological dependence relative to drugs
in III
Examples: stimulants and depressants including Valium, Xanax,
Librium, phenobarbital, Darvon
Kendall/Hunt

8. Controlled Substances Act, continued
Chapter 7
Controlled Substances Act, continued
Schedule V—low potential for abuse relative to drugs in IV; currently accepted medical use in the U.S.; abuse may lead to limited physical or psychological dependence relative to drugs in IV
Examples: codeine found in low doses in cough medicines
Kendall/Hunt

9. Chapter 7
Illegal or Illicit?
An illegal drug is a drug that is against the law to have, use, or distribute.
An illicit drug is a legal drug used in an inappropriate or illegal way.
Kendall/Hunt

10. Human Components Used for Drug Analysis
Chapter 7
Human Components Used for Drug Analysis
Blood
Urine
Hair
Gastric contents
Bile
Liver tissue
Brain tissue
Kidney tissue
Spleen tissue
Vitreous humor of the eye
Kendall/Hunt

11. Physicians’ Desk Reference
Chapter 7
Physicians’ Desk Reference
PDR—A Physicians’ Desk Reference is used to identify manufactured pills, tablets, and capsules. It is updated each year. This can sometimes be a quick and easy identifier of the legally made drugs that may be found at a scene. The reference book gives a picture of the drug and states whether it is prescription, over-the-counter, or a controlled substance; it gives more detailed information about the drug as well.
Kendall/Hunt

12. Drug Identification Screening or presumptive tests Spot or color tests
Chapter 7
Drug Identification
Screening or presumptive tests
Spot or color tests
Microcrystalline test—
a reagent is added, producing a crystalline precipitate that is unique for a certain drug
Chromatography
Confirmatory tests
Spectrophotometry
Ultraviolet (UV)
Visible
Infrared (IR)
Mass spectrometry
Kendall/Hunt

13. Drug Identification, continued
Chapter 7
Drug Identification, continued
Screening or presumptive tests only tell that the drug is possibly present.
Confirmatory tests tell that the drug is positively present.
(Screening tests are easier, cheaper, and quicker to use.)
Kendall/Hunt

14. Presumptive Color Tests
Chapter 7
Presumptive Color Tests
Marquis—turns purple in the presence of most opium derivatives and orange-brown with amphetamines
Dille-Koppanyi—turns violet-blue in the presence of barbiturates
Duquenois-Levine—turns a purple color in the presence of marijuana
Van Urk—turns a blue-purple in the presence of LSD
Scott test—color test for cocaine; blue
Kendall/Hunt

15. Chapter 7
Chromatography
A technique for separating mixtures into their components
Includes two phases—a mobile one that flows past a stationary one
The mixture interacts with the stationary phase and separates
Kendall/Hunt

16. Types of Chromatography
Chapter 7
Types of Chromatography
Paper
Thin-layer (TLC)
Gas (GC)
Pyrolysis gas (PGC)
Liquid (LC)
High-performance liquid (HPLC)
Column
Kendall/Hunt

17. Paper Chromatography Stationary phase—paper
Chapter 7
Paper Chromatography
Stationary phase—paper
Mobile phase—a liquid solvent
Capillary action moves the mobile phase through the stationary phase.
Kendall/Hunt

18. Thin-layer Chromatography
Chapter 7
Thin-layer Chromatography
Stationary phase—a thin layer of coating (usually alumina or silica) on a sheet of plastic or glass
Mobile phase—a liquid solvent
Kendall/Hunt

19. Chapter 7
Retention Factor (Rf)
This is a number that represents how far a compound travels in a particular solvent.
It is determined by measuring the distance the compound traveled and dividing it by the distance the solvent traveled.
If the Rf value for an unknown compound is close to or the same as that for the known compound, the two compounds are likely similar or identical (a match).
Kendall/Hunt

20. Gas Chromatography Phases Stationary—a solid or a
Chapter 7
Gas Chromatography
Phases
Stationary—a solid or a
viscous liquid that lines a tube
or column
Mobile—an inert gas like nitrogen or helium
Analysis
Shows a peak that is proportional to the quantity of the substance present
Uses retention time instead of Rf for the qualitative analysis
Kendall/Hunt

21. Uses of Gas Chromatography
Chapter 7
Uses of Gas Chromatography
Not considered a confirmation of a controlled substance
Used as a separation tool for mass spectroscopy (MS) and infrared spectroscopy (IR)
Used to quantitatively measure the concentration of a sample. (In a courtroom, there is no real requirement to know the concentration of a substance. It does not affect guilt or innocence.)
Kendall/Hunt

22. Confirmatory Tests: Spectroscopy
Chapter 7
Confirmatory Tests: Spectroscopy
Spectroscopy—the interaction of electromagnetic radiation with matter
Spectrophotometer—an instrument used to measure and record the absorption spectrum of a chemical substance
Kendall/Hunt

23. Spectrophotometry Components A radiation source A frequency selector
Chapter 7
Spectrophotometry
Components
A radiation source
A frequency selector
A sample holder
A detector to convert electromagnetic radiation into an electrical signal
A recorder to produce a record of the signal
Types
Ultraviolet
Visible
Infrared
Kendall/Hunt

24. Infrared Spectrometry
Chapter 7
Infrared Spectrometry
Material absorbs energy in the near-IR region of the electromagnetic spectrum
Compares the IR light beam before and after it passes through a transparent sample
Result—an absorption or transmittance spectrum
Gives a unique view of the substance; like a fingerprint
Kendall/Hunt

25. Chapter 7
Mass Spectrometry
Gas chromatography has one major drawback: It does not give a specific identification. Mass spectrometry cannot separate mixtures. By combining the two (GC-MS), constituents of mixtures can be specifically identified.
Kendall/Hunt

26. Mass Spectrometry, continued
Chapter 7
Mass Spectrometry, continued
In a mass spectrometer, an electron beam is directed at sample molecules in a vacuum chamber. The electrons break apart the sample molecules into many positive-charged fragments. These are sorted and collected according to their mass-to-charge ratio by an oscillating electric or magnetic field.
Kendall/Hunt

27. Mass Spectra Each molecular species has its own unique mass spectrum.
Chapter 7
Mass Spectra
Each molecular species has its own unique mass spectrum.
Kendall/Hunt

28. IR Spectrophotometry and Mass Spectrometry
Chapter 7
IR Spectrophotometry and Mass Spectrometry
Both work well in identifying pure substances.
Mixtures are difficult to identify in both techniques.
Both are compared to a catalog of knowns.
Kendall/Hunt

29. People of Historical Significance
Chapter 7
People of Historical Significance
Arthur Jeffrey Dempster was born in Canada, but studied at and received his PhD from the University of Chicago. He began teaching physics there in In 1918, Dempster developed the first modern mass spectrometer. His version was over 100 times more accurate than previous ones and established the basic theory and design of mass spectrometers that is still used to this day.
Kendall/Hunt

30. People of Historical Significance, continued
Chapter 7
People of Historical Significance, continued
Francis William Aston was a British physicist who won the 1922 Nobel Prize in Chemistry for his work in the invention of the mass spectrograph. He used a method of electromagnetic focusing to separate substances. This enabled him to identify no fewer than 212 of the 287 naturally occurring elemental isotopes.
Kendall/Hunt